Pluto wows with first close view of ice mountains on its surface

Up close and personal (Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

It’s the image we’ve all been waiting for, and the crowd goes wild. Taken yesterday morning as New Horizons flew past Pluto at nearly 14 kilometres per second, this picture shows what the dwarf planet looks like in incredible detail.

But it’s nothing like what we expected. “It feels terrible,” joked mission lead Alan Stern in a press conference earlier today. “There is a lot of depression in the science team, they don’t understand anything.”

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It’s very likely the mountains on the surface of Pluto, just as majestic as the rocky ones we have on Earth, are made from frozen water. And in a big surprise, there are no craters in this first high-resolution image of the surface. That means Pluto is a geologically active world, its surface perhaps less than 100 million years old.

It’s a textbook-tearing moment. Until New Horizons arrived, most people thought Pluto would be similar to Triton, an icy moon of Neptune. “It’s nothing like Triton,” said John Spencer, one of the team’s geologists. The surface is far more varied, and they don’t know why.

There’s another important difference. The pull of gravity from the gas giant Neptune distorts Triton, remoulding its surface features, but that can’t happen on Pluto.

Something else must be providing energy from its interior – perhaps radioactive elements that have held their heat for longer than thought possible, or a liquid ocean that is gradually freezing, releasing energy to the surface. “I think that’s going to send a lot of geophysicists back to the drawing board,” said Stern.

Pluto was the star of the show today here at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, but the results from its moons also came thick and fast. We got our first look at Hydra, a tantalisingly blurred and asymmetric blob. And we discovered that Charon is just as varied as Pluto.

The dark polar region on Charon, informally nicknamed Mordor, is one of its most intriguing features. There is also a gigantic stretch of cliffs and troughs running for 600 miles across the moon, and deep canyons elsewhere. In the southern regions, smoother terrain reveals that Charon must also be active, something no-one expected.

The past few days have been a rollercoaster of emotion for all involved. The team were particularly proud to rename the much-loved heart region on Pluto as Tombaugh Regio, in honour of the man who discovered Pluto in 1930.

But this mission isn’t over, as New Horizons will be sending data back to Earth for the next 16 months.

We’ll being seeing much, much more of this incredible world and its moons, but even this first glimpse is teaching us an incredible amount about the Kuiper belt, the third region of the solar system that we have now finally begun to expore. “I don’t think any one of us could have imagined it was this good of a toy store,” said Stern.